<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./lib/vue-2.4.0.js"></script>
</head>
<body>
    
    <div id="app">
        <input type="button" value="浪起来" v-on:click="lang">
        <input type="button" value="低调" @click="stop">
        <h4>{{msg}}</h4>
    </div>
    <script>
         var vm = new Vue({
            el:'#app',
            data:{
                msg:'猥琐发育，别浪~~！',
                intervalId:null
            },
            methods:{
                lang(){
                    //console.log(this.msg)
                    if(this.intervalId!=null) return;
                    this.intervalId=setInterval(()=>{
                        var start = this.msg.substring(0,1)
                        var end = this.msg.substring(1)
                        this.msg = end + start
                    },400)
                    //console.log(start)
                    //console.log(end)
                    //console.log(this.msg)
                },
                stop(){
                    clearInterval(this.intervalId)
                    //console.log(this.intervalId)
                    this.intervalId = null;
                }
            }
        })
    </script>
</body>
   
</html>